Hardened steel tool



HARDENED STEELTOQL.

4, 1920. 4, Patnted DGO. 6, 1921..

UNITED STATEST PTENT OFFICE.

WILLIAM B. SULLIVAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO RICH TOO-L COMPANY, OF CHICAGO, ILLINOIS, A CORPOBATION OF ILLINOIS.

HARDENED STEEL TOOL.

Specifieation of Letters Patent.

Application filed February 24, 1920. serial No. 360,659.

To all whom it may concern:

Be it known that I, XVILLIAM B. SULLIVAN, a citizen of the United States, and resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Hardened Steel Tools, of which the following is a specification, and which are illustrated in the accompanying drawings, forming a part thereof.

The invention relates to steel tools and particularly to those which are hardened by heat treatment and which are of such shape as to present abrupt changes in size between different parts. The object of the invention is to provide a hardened steel tool of improved design whereby there is a more gradual chan 'e in the mass of metal employed in diferent parts of the tool than would otherwise result from abrupt changes in external configuration or size. A feature of the invention also serves to facilitate the dissipation of heat from the head of the tool when used upon hot work.

In the accompanying drawings;

Figure 1 is a perspective view showing one form of hardened steel tool embodying the invention;

Fig. 2 is a central longitudinal sectional View of the same;

Fig. 3 is an end view of the tool illustrated in Figs. 1 and 2, and

Fig. 1 is a side elevation showing the tool heretofore in common use for the same purpose, partly broken away.

The particular tools represented in the drawing are designed for use with so-called air hammers which operate by repeated blows of a piston (not shown) upon the end of the shank, as 10, (Fig. 4) of the tool while the head 11 of the tool is held against the work. In order that such a tool may be effective in service, it should present as little inertia as possible under the impacts of the said piston. It is therefore imperative that the weight ot' the tool should not be excessive. For this purpose the tool is constructed with its shank 10 of reduced diameter as compared with the size of the head 11.

On the other hand, to prevent ejection of the tool from the air hammer in event of operation of the hammer when the head of the tool is not in contact with the work, the tool must be formed to present a forwardly facing annular shoulder, as 12, of relatively large diameter in rear of the operative part of the head. Usually there is also a cylindrical surface, as 13, extencling forwardly from the said shoulder 12. In practice this cylindrical part of the tool slides within the retainer (not shown) of the air hammer and the shoulder 12 serves to limit the said slid- V ing movement in one direction.

Patented Dec. 6, 1921. 4

It accordingly follows that the head 11 and shank 10, of the tool, are not only widely different in size but that the expan- Sion from the size of the shank '10 to the size of the head 11 is quite abrupt. There is thus a wide difference in the mass of metal immediately adjacent the two sides of the plane, as 14-14, at Which the shank 10 joins the head 11.

It is also requisite of tools employed with air hammers, that they should be hardened throughout. This is for the reason that wear is to be resisted at both-ends of the tool while hardness between the ends is required to resist distortion under the rapidly repeated blows of the said air hammer piston. Owing to the abrupt change in the mass of the tool at the plane indicated by the said line 1 1-1 1 on Fig. 4, the hardening of the tool may result in presence of cooling strains at this place, and in the use of the tool this part is subjected to the greatest strain and may develop, fatigue. In any event fraoture and complete separation of the head and shank of the tool frequently occur in service and these conditions are believed to be contributing causes.

In carrying out the invention, the head of the tool adjacent the shank is formed to provide a tapering recess preferably without change in the exterior dimensions of the tool, the largest part of the recess being at the plane of union between head and shank. The change in the relative mass of metal between head and shank is thereby made much more gradual than has heretofore been the case in tools of like shape.

As shown in Figs. 1, 2 and 3, the head 16 of the tool is recessed in the manner just indicated by being provided with a plurality of slots 15 of varying depth, the said slots being equally spaced about the head 16 adjacent the shank 17. When these slots are provided, the floor 18 of each slot is preferably flush with the exterior surface of the shank 17 at one end and gradually approaches the exterior surface of the head 16 with which it merges intermediate the ends a a large measure, increased rgidity ofthe of the head, as at 19. The said forwardly impair their usefulness in coperation With the correspondng parts of the air hammer (not shown). l

On the li other hand, When the tool is grally formed cylindrical head and shank arquenched from a high temperature, "for hardening the same, sudden change in the rate of coolin and shank 17 is avoided and coolin'g strains areiless likely to be develo ed at that place or elsewhere in. the tool. n fact, the presence of the slots serves to increase the rate of coolin of the head 16 When the tool is quenched 'or hardenig and these slots 'likewise :facilitate the (lissipation of heat from the head When the tool is used upon `hot ork, as in rivet setting. Furthermore,

the provsion of the slots 15 also avoids, in

tool in the adjacent part of the head 16 as compared With the shank 17. The strains tendency at the union of the head 16,

to which the tool is subjected in service are therefore less concentrated at the union of the head andshankthan in the case' of tools of the form illustrated in Fig. 4 and the to fracture at this place is greatly reduced.

'I claim as nyinvention:

A hardened steel tool comprising interanged in longitudinal alinement but difiering substantially in size andexpanding abruptly between the shank and head, a part of the head of the tool adj acent the shankbeing provided With an annular series of longitudinal grooves of gradually diminishing depth leading from the union of the head With the shank and disappearing entirely intermediate the length of the head, the bottorns 'of the grooves being flush With the exterior of' the adjacent part of the shank at olie end and ith the exterior of the adjacent part of the head at the other end ofthe grooves WILLIAM BfsUL IVAN 

